The present invention relates to an electrophotographic photoreceptor, and to an image forming apparatus and a process cartridge, which employ the electrophotographic photoreceptor.
Conventionally, thermoplastic resin which has been used in an electrophotographic photoreceptor (hereafter, merely referred to as a photoreceptor), especially in a so-called organic photoreceptor, tends to be damaged under an environment of high temperature and high humidity. Therefore, halftone unevenness caused by surface flaws on the photoreceptor becomes problems in many cases.
As a solution for these problems, an improvement has been tried to provide a resin surface layer on the surface of a photoreceptor. Especially, in order to raise the surface hardness, an investigation to increase the strength of resin with a crosslinking reaction by utilizing energy, such as heat or light, has been conducted (refer to the official gazette of Japanese Unexamined Patent Publication No. 9-281736). There are various methods of increasing a crosslinking density. Among them, a method of conducting a crosslinking reaction with light may be suitable from a viewpoint of the advance degree of a crosslinking reaction (refer to the official gazette of Japanese Unexamined Patent Publication No. 2001-125297).
Among the crosslinking reaction with light, in the case that metal oxides are subjected to a surface treatment with a compound having a radical polymerizable functional group and the treated metal oxides are made to react so as to form a hardened surface layer on a photoreceptor, the resultant photoreceptor is excellent in wear resistance and can maintain a good cleaning ability for a long term. However, in addition to the matter that the wear resistance is improved, it has also turned out that if an unreacted radical polymerizable functional group exists on a part of the surface of the photoreceptor, the photoreceptor has a problem that image blurring is caused on the part.